Void-forming construction for pre-cast beams



March 13, 1962 E. A. SHUXTEAU ET AL 3,024,513

VOID-FORMING CONSTRUCTION FOR PRE-CAST BEAMS Filed Feb. 5, 1959 2 Sheets-Sheet 1 Z7 .50 I i l i i i i W\ 23 J1 Z5 11 l f 71216722 5715 i i [gems dj/azxifczu 30 2a w \faaepk J Head @164z4fM Q2 March 13, 1962 E. A. SHUXTEAU ET AL 3,024,513

VOID-FORMING CONSTRUCTION FOR PRE-CAST BEAMS Filed Feb. 5, 1959 2 Sheets-Sheet 2 nits The present invention relates to the internal supporting means for use in the manufacture of pre-cast, hollow, concrete beams.

Among the important objects of the invention are the provision of effective and easily handled par-ts, formed of sheet material which may be prepared in flat, compact form, which may readily be shaped or folded into interlocking groups and quickly and easily assembled within a hollow, void-forming member designed to be disposed longitudinally of a casting form and enclosed within a concrete beam which is formed around the void-forming member.

In the manufacture of pre-cast, hollow concrete beams an important consideration is to provide a void-forming member of light, strong and inexpensive material, capable of withstanding the weight of wet concrete when poured around the void-forming element, and also to provide a construction sufiiciently sturdy to resist accidental deformation due to the use of tampers, vibrators and other tools employed in removing air pockets from the concrete while the beams are being poured.

In the drawings, illustrating a preferred embodiment of the invention FIG. 1 is a perspective view of a portion of a hollow concrete beam indicating in broken lines a void-forming member enclosed within the beam;

FIG. 2 is a somewhat enlarged, cross-sectional view, taken along line 22 of FIG. 1, as respects the beam, but additionally showing the beam enclosed on three sides by a hollow form within which the beam may be cast, and showing the internal reinforcing parts for the voidforming member;

FIG. 3 is a fragmentary sectional view, taken along line 3-3 of FIG. 2, omitting the hollow form, and showing the void reinforcing elements at right angles to their position illustrated in FIG. 2;

FIG. 4 is a fragmentary sectional view taken along line 44 of FIG. 3;

FIG. 5 is an exploded perspective view showing two companion reinforcing parts for the void-forming member as such parts appear when about to be placed in assembled relation;

FIG. 6 is a perspective view with parts broken away, showing one end portion of a completed hollow concrete beam, showing a section indicating the relationship of the reinforcing rods to the void-forming member, and another section which illustrates the relationship of the voidforming member and its reinforcing elements;

FIG. 7 is a lan view on a somewhat reduced scale of the blank from which the tubular void-forming member may be constructed;

FIG. 8 is a plan view of a form of closure for closing the ends of the tubular void-forming member; and

FIGS. 9 and 10 are plan views respectively of the blanks from which the companion reinforcing elements may be formed,

Essentially the void-forming construction comprises a multi-walled, tubular member of foldable sheet material, such as corrugated paperboard, which is adapted to be placed in a suitable form into which is poured wet concrete to surround the void-forming member and form a hollow beam. A plurality of reinforcing elements are fitted within the tubular member. These reinforcing ele-, ments may be of any suitable sheet material, such as corrugated paperboard, and are preferably formed of a number of pairs of companion elements. One of the elements is in the form of a fiat panel the central portion of which is folded against itself to form an outstanding rib. The other element is preferably folded to assume a channel shape which provides a flat central portion and two edge flanges. These flanges are preferably notched and fitted over the rib on the first element, such rib also being notched whereby the edges of the flanges may bear upon the flat panel portions of the first element and the free edge of the rib will bear against the fiat central portion of the second element. The edges of both elements preferably are in contact with the interior surface of the tubular member when in assembled relation to serve as an effective support to resist any tendency of the tubular member to collapse under the weight of the wet concrete during formation of the hollow beams.

Referring more particularly to the drawings, the complete hollow concrete beam is indicated as a whole at 10. See FIGS. 1 and 6. The void-forming tubular member, indicated as a Whole at 11, occupies a central position within and extends longitudinally of the beam. In the process of manufacture a trough shaped casting form, indicated at 12 in FIG. 2, may be provided. A group of U-shaped reinforcing rods 13, 13 will be placed upright in the form, followed by the insertion of a group of longitudinal reinforcing rods 14, 14. After wet concrete is placed in the form to the proper level a plurality of tubular members 11, 11 will be placed upon this layer of concrete. Additional longitudinal reinforcing rods and U-shaped transverse rods are now placed within the form, surrounding the tubular member.. The form is then completely filled with additional wet concrete. When the concrete has become set the beam will be re moved from the form and transported to the place of use. It is to be understood that the formation of the hollow concrete beam is generally conventional and forms no part of the present invention.

The tubular member 11 may be of any convenient length. In practice, several of such tubular members, placed end to end, are utilized in the preparation of a concrete beam. The blank for the tubular member, shown in FIG. 7, may comprise a sheet of corrugated paperboard scored longitudinally as indicated at 16, 16 to provide widened or blunt corners. See FIGS. 2 and 6. The scores adjacent the longitudinal edges of the blank provide sections which are arranged to overlap and may be attached to each other as by means of gummed tape, stapling or gluing. See FIG. 2.

Closure elements, such as indicated at 17 (see FIGS. 6 and 8) are provided to close the ends of the tubular members. The central panel of the closure is shaped to conform with the outside contour of the tubular member. Flap extensions 18, 18 are provided on the sides and narrow flap extensions 19, 19 are provided to conform to the widened or blunt corners of the tubular member. The closures may be assembled in place by gluing or by sealing the flaps flat against the outside of the tubular member by strips of gummed tape.

The inner reinforcing parts for the tubular member may be formed as companion pairs of elements and are preferably constructed from blanks cut and scored as illustrated in FIGS. 9 and 10. The element 20, shown in FIG. 9, has a central portion defined by score lines 21, 21 and 21a to provide two adjacent narrow panels 22, 22 and two side panels 23, 23. The panels 22, 22 are capable of being folded out of the plane of the panels 23, 23 so as to contact each other face to face and together form what may be termed a stiffening rib. When the narrow panels 22, 22 are folded together the outer edges will approach each other and the contour which the element will then assume substantially conforms to the inner periphery of the tubular element. As shown in FIGS. 2, 3, 4 and 6, the element thus set-up provides reinforcing panels 23, 23 in aligned relation, which disposed within tubular member 11 extend transversely of the tubular axis thereof. It is to be noted that the outer corners of panels 23, 23 are cut diagonally, as indicated at 24, 24, to conform with the widened corners of the tubular member.

The element 25 shown in FIG. 10, may be formed as a rectangular blank, scored at 26, 26 to provide a central panel 27 and two edge panels 28, 28, foldable at right angles to the central panel to form stiffening flanges.

For the purpose of assembling the elements 20 and 25 into a single supporting and reinforcing unit the rib formed by narrow panels 23, 23 is preferably slotted at 29, 29 to receive the edge portions of the narrow panels or flanges 28, 28. The slots 29 are preferably formed of a length equal to about one-half the width of the rib and slots 30, 30 are formed in the panels or flanges 28 extending about half way of their width whereby the two sets of cooperating slots allow the free edges of flanges 28 to come to rest against the surface of the element 20. The free edge of the rib formed by panels 23, 23 will likewise be brought into contact with the inner face of central panel 27. The two companion elements, when thus assembled, form a relatively rigid unit and present edge portions which may bear against the inner faces of the walls of the tubular member to resist effectively any inward collapsing movement of such walls. As best illustrated in FIGS. 2 and 6, the opposite ends of the element 25 and adjacent edges of the panels 23 are in contact with the inner surfaces of two opposite walls of the tubular member. Likewise the ends of the stiffening rib formed by panels 22, 22 and the adjacent edges of panels 23, 23 are in contact with the inner faces of the other two opposite walls of the tubular member.

By filling the tubular member with the joined companion elements 20 and 25 it is obvious that the tubular element, when employed within the beam casting form, will have a high degree of resistance to the pressure of the wet concrete.

While both the flanges 28 and the projecting rib section on element 20 have been shown as slotted it is apparent that deeper slots may be formed in the rib section so as to receive the full width of the flanges 28, in which case such flanges need not be slotted.

The blanks for the tubular member and the reinforcing elements 20 and 25 may be shipped in flat form to the point of use and there set up as needed, preferably by employing gummed tape to secure together the free edges of the blank of the tubular member and to secure the flaps of the closure to the ends of the tubular member side walls. After the tubular member has been set up and a closure applied to one end a suflicient number of the companion reinforcing elements 20 and 25 will be assembled and inserted into the tubular member until it is completely filled. The other end closure will then be secured on the tubular member after which it may be placed within the form. As soon as a sufficient number of completed tubular members in end-to-end relation have been placed in the form the necessary reinforcing rods may be secured in place, followed by completion of the filling of the form with wet concrete.

For the purpose of preventing undue absorption of moisture by the void-forming parts, they are preferably manufactured from corrugated paperboard which has been suitably coated or impregnated with water repellant material, such as size or wax.

While the present description sets forth a preferred embodiment of the invention, various changes may be made in the construction without departing from the spirit of the invention, and it is therefore desired that the present embodiment be considered in all respects as illustrative and not restrictive, reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

We claim:

1. An expendable enclosed cellular reinforced collapsible core device formed of paperboard and adapted to be permanently positioned Within a mass of concrete to form a void in an elongated hollow precast concrete beam, comprising: an elongated tubular casing having end closures at opposite ends thereof to define a closed cavity; and a plurality of cellular reinforcing members arranged in continuous abutting sandwiched relationship throughout the length of the cavity between said closures; each of said cellular reinforcing members including a panel element disposed to extend transversely of the cavity in a direction normal to the longitudinal axis of the cavity and having substantially the same area as the cross-sectional area of the cavity, a rib element integral with and projecting from one side of the panel element and extending transversely of the cavity parallel to the panel element and normal to the longitudinal axis of the cavity, and a channel element also extending transversely of the cavity normal to the longitudinal axis of the cavity and including a generally flat center web extending parallel to the panel element and having projecting therefrom integral flange means disposed in interlocking engagement with said rib element.

2. A core device according to claim 1, wherein said rib element and said channel element flange means have mutually facing notches which afiord said interlocking engagement.

3. A core device according to claim 1, wherein said panel element and said channel element are each formed of a single sheet of foldable paperboard which has been cut, scored, and folded to provide the respective rib and flange means.

References Cited in the file of this patent UNITED STATES PATENTS 1,258,923 Margua et al Mar. 12, 1918 1,999,361 James et a1 Apr. 30, 1935 2,192,183 Deutsch May 5, 1940 2,766,924 Cormier Oct. 16, 1956 2,823,442 Miller et al Feb. 18, 1958 FOREIGN PATENTS 762,397 France Jan. 22, 1934 

